Well conduit cementing adapter tool

ABSTRACT

A cementing adapter housing for use in cementing well conduits in a well by connecting with the drilling kelly to maintain desired fluid circulation in the well through a flow passage while providing a flow connection for introduction of the fluid cement into the bore of the well conduit to be cemented. A plug means releasably secured in the housing is actuated for release when desired to prevent contamination of the fluid cement by circulating fluid when moving the cement into position for hardening. The housing is formed in two sections releasably secured together in a manner to enable rapid disassembly at the completion of the cementing operation.

United States Patent Duke 1 Dec. 16, 1975 WELL CONDUIT CEMENTING ADAPTERPrimary ExaminerErnest R. Purser TOOL Attorney, Agent, or Firm-Pravel &Wilson [76] Inventor: John A. Duke, 1311 Beaumont St.,

Apt. 44, Baytown, Tex. 77520 [57] ABSTRACT Filedl y 28, 1974 A cementingadapter housing for use in cementing [21] APPL N03 473 487 well conduitsin a well by connecting with the drilling kelly to maintain desiredfluid circulation in the well through a flow passage while providing aflow connecl l 155 tion for introduction of the fluid cement into thebore [51] Int. Cl: E21B 33/05 f th w ll conduit to be cemented. A plugmeans re- [58] Field of Search 166/70, 88 l bl r d in the housing isactuated for release when desired to prevent contamination of the fluidcel References Cited ment by circulating fluid when moving the cementUNITED STATES PATENTS into position for hardening. The housing is formedin 2,713,909 7/1955 Baker 166/70 two Seciions releasably Securedtogether in a manner 3,322,197 5/1967 Baker et al. 166/70 enable rapiddisassembly at the Completion of the 3,444,928 5/1969 Pitts 166/70 n ingoperation. 3,828,852 8/1974 Delano 166/70 17 Claims, 2 Drawing Figures 1l J ,L

J5 fit ll" 32 I I! 22.6. i

4 40 40a 3 a, 35a, 39 :5 10.6 42a 38a 41 d- 426 WELL CONDUIT CEMENTINGADAPTER TOOL BACKGROUND OF THE INVENTION This invention relates to thefield of a well conduit adapter for use during well cementingoperations.

The use of plug containers during well cementing operations is old andwell known. For an example of a description and illustration of theprior art and for the details of known well cementing apparatus andprocedures, specific reference is hereby made to pages 2293 and 3303 ofthe Catalogue of Oil Field Equipment and Services, 29th Edition,1970-71, published by World Oil, Houston, Tex.

Previously, the prior art plug containers were connected to the drillingfluid circulating pumps by disconnecting the flexible line at the rotaryswivel and connecting with the plug container. Such a procedure was timeconsuming and there was a substantial risk that the casing would becomestuck in the well bore during this period. In addition, the prior artplug containers were not designed with sufficient strength to supportthe casing in the well during the cementing operation.

SUMMARY OF THE INVENTION This invention relates to I a new and improvedwell conduit cementing adapter tool. A well cementing adapter toolhaving a housing-for connection with the well conduit to be cemented andthe drilling kelly. The housing forms a flow passage for enablingcirculation through the well conduit and a flow connection for theintroduction of fluid cement while supporting the well conduit in thebore hole. A new and improved plug body releasably secured in the flowpassage is actuatable for movement from the housing to prevent the fluidcement from contamination by circulating fluids. The housing is formedin two sections releasably secured together in a manner to enable rapiddisassembly at completion of the cementing operation. An object of thepresent invention is to provide a new and improved welll conduitcementing adapter tool.

'A further object of the present invention is to provide a new andimproved well conduit cementing adapter tool that may be rapidlydisassembled at completion of the cementing operation.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view, in section, ofthe cementing adapter tool of the present invention operably installedbetween the drilling kelly and the well conduit to be cemented; and

FIG. 2 is an exploded side view illustrating the separated housingsections and the plug means of the cementing adapter tool.

DESCRIPTION OF THE PREFERRED EMBODIMENT The well conductor cementingadapter tool of the present invention, generally designated A in theFigs. is used for cementing well conduits or casing C in a well.

In a typical well cementing operation, as is well known in the art, thecasing C is lowered into the well bore hole (not illustrated) to thedesired location for cementing in the annular area between the wellcasing C and the well of the bore hole to seal and support the casing Cin the well. To prevent the casing C from becoming stuck by engaging ofthe walls of the bore hole during lowering, it is common practice tocirculate drilling fluids down the bore B of the casing C and out of thecasing C into the annular area between the casing C in the walls of thebore hole for flowing back to the surface (not illustrated). When thecasing C is located at the desired location in the well, a first orbottom plug (not illustrated) may be inserted into the bore B of thecasing C. Often this was done by prior art plug containers which weremounted at the top of the casing C to be cemented and which provided aconnection for the flexible hose that normally ran to the drillingswivel (not illustrated) of the drilling rig (not illustrated) forcirculating the drilling fluids. The prior art plug containers providedconnections for the introduction of the fluid cement into the bore B ofthe casing C for circulation down the bore B of the casing C and intothe well annulus where the cement was allowed to harden or set forholding thewell casing C in position. The casing C may be either asurface casing, a production casing or may constitute any well conduitdesired to be cemented in the well.

As illustrated in FIG. 1, the adapter tool A includes a housing 10having suitable means, such as threaded pin connection 12, mounted atthe lower end of the housing 10 for connecting the housing 10 with theupper end of the well casing C to be cemented. At the upper end of thehousing 10, suitable means, such as box threads 14, are provided forconnecting the housing 10 with a drilling kelly K in the well knownmanner. The housing 10 is formed of sufficient strength to support thewell casing C at the desired location in the well for cementing.

The substantially tubular adapter housing 10 preferably forms aconcentric passageway 16 therethrough for communicating the bore or flowpassage F of the kelly with the bore B of the well conduit C forcirculating drilling fluids and the like from the drilling swivel (notillustrated) and kelly flow-passageway F through the flow passageway 16of the housing 10 and the bore B of the well casing C in the well knownmanner.

As best illustrated in FIG. 2, the housing 10 includes an upper housingsection 20 releasably secured to a lower housing section 22 by suitablemeans, such as the illustrated threaded engagement. Left-handed boxthreads 23 on the lower end of the upper section 20 engage left-handedbox threads 24 (FIG. 1) on the upper end of the lower section 22. Whileright-handed thread engagement may be utilized, left-hand engagement ispreferred for the threads 23 and 24 in order that the kelly powerspinner S (FIG. 1) can be utilized at the completion of the cementingoperations to enable a more rapid resumption of drilling operations bythe drilling rig as will be set forth in greater detail hereinafter. Asthe normal right-handed rotation of the kelly K will tend to disengagethe threads 23 and 24, suitable means are provided for preventinginadvertent disengagement of the threads 23 and 24. The lower housingsection 22 forms an exterior surface 22a having a plurality of equallycircumferentially spaced lugs 26 formed thereon adjacent the upperannular shoulder 22b of the lower section 22. Movably mounted along theexterior surface 22a of the lower section 22 is a ring member 28 havinga corresponding plurality of inwardly projecting lugs or fingers 28a(FIG. 1) which are positioned between the lugs 26 when the ring 28 is ina first or locking position (FIG. 1) to engage the lugs 26 for blockingrelative circumferential rotation between the lower housing 22 and thering 28. The ring 28 is longitudinally movable downwardly to a second orrelease position (FIG. 2) with the inwardly projecting fingers 28aspaced or released from the lugs 26 for enabling relativecircumferential rotation between the lower housing 22 and the ringmember 28. Suitable means, such as threaded set screw 29, may beemployed to hold the ring 28in the desired position. The ring member 28is provided with a pair of upwardly projecting extensions 28b and 280 atcircumferentially spaced locations thereon.

The upper housing section 20 forms an exterior surface 20a having a pairof protruding portions or members 20b and 20c formed thereon incircumferentially spaced relationship corresponding to that of theupwardly extending portions 28b and 28c, respectively. When the ring 28is in the upper or locking position (FIG. 1) the upwardly projectingextensions 28b and 28c engage the protruding members 20b and 200,respectively to prevent relative circumferential rotation between theupper section 20 and the ring 28. As the ring 28 is blocked fromrelative circumferential rotation with respect to the lower housing 22because of the engagement of the lugs 26 with the projections 26a of thering 28, relative rotational movement between the upper section 20 andthe lower section 22 is thus prevented by right-hand rotation of thehousing by the kelly K.

Should the threads 23 and 24 have sufficient friction therebetween toavoid disengagement when power is applied to the spinner S, additionalforce to effect separation may be supplied using the ring 28. Normally,the ring 28 will be positioned in order that the upwardly projectingextensions 28b and 280 are positioned in the path of the protrudingmembers b and 200 to block the relative circumferential rotation betweenthe upper section 20 in the lower section 22. By dropping the ring 28 tothe lower position and then rotating the ring to move into lockingengagement with the lugs 26 on the other side of the protruding members20b and 20c an additional force from the lower member may be imparted tothe upper member to effect release of the threads 23 and 24. With thelocking ring 28 moved back to the upper position but on opposite sidesof the protruding members 20b and 200, suitable bolts 32 and 33 may berun through threaded openings 30 and 31, respectively, which are formedthrough the ring member extensions 28b and 280, respectively forengagement with the protruding members 20b and 200. By suitabletightening of bolts positioned in the openings 30 and 31 an additionaltorque force is imparted to the extensions 20b and 200 for assisting thespinner S in effecting disengagement of the threads 23 and 24. Or-

dinarily, the spinner S will have more than sufficient rotational powerto disengage the threads 23 and 24 and it will not ordinarily benecessary to use bolts 32 and 33 in the openings 30 and 31 to assist indisengaging threads 23 and 24. It should be noted also, that bolts inthe openings 30 and 31 may be reversed when the upwardly projectingextensions 28b and 28c are in the usual rotation blocking position andbolts 32 and 33 may then be employed in lieu of set screw 29 to hold thelocking ring 28 in the upper or locking position. It should also beapparent that the bolts 32 and 33 in the threaded openings 30 and 31 maybe used in conjunction with the set screw 29 to hold the locking ring inthe desired position.

As illustrated in FIG. 1, the housing 10 includes one or more threadedcement flow connections 34 and 34a which are preferably located with thelower section 22 adjacent threads 24. The flow connections 34 and 34aare threadedly connected by conduits 35 and 35a, respectively, havingsuitable valving (not illustrated) with the source of fluid cement (notillustrated) to be used in cementing the well casing C in the well.While the location of flow connections 34 and 340 with the flow passage-16 of the housing 10 need only be at some intermediate location of theupper and lower ends of the housing 10, the illustrated location ispreferred, as the conduits 35 and 35a provide a lower limit stop supportfor the ring 28 in the lower or released position.

Located in the flow passage 16 above the cementing flow connections 34and 34a may be located a check valve means 36 for blocking flow from theflow passage 16 of the housing 10 into the flow passage F of the kellyK. The illustrated form of the check valve 36 is a pivoted flapper valvethat is spring loaded to the upper or closed position for blocking theupwardly flow in the flow passage 16 and which is pivoted downwardly byflow from the kelly K to the position illustrated in phantom forenabling flow from the flow passage F into the flow passage 16 of thehousing 10. The valve 36 pivots about an axis provided by attachmentpivot pin 36a secured to the housing 10 when moving the valve 36 to andfrom sealing engagement with the upper portion 20 of the housing 10.Such spring biased closed check valves are old and well known to thoseof ordinary skill in the art and disclosed in the prior art patents.

Releasably secured in the flow passage 16 below the cementingconnections 34 and 34a is a plug means, generally designated 37,including a plug body 38 having a longitudinal opening of predeterminedsize formed therethrough for enabling circulation flow of fluid throughthe flow passage 16 to normally pass the plug body 38. Suitable annularseal means provided by the packing 39 mounted with the plug body 38 forblocking flow of fluid between the plug body 38 and the housing 10 todirect the flow of fluid through the opening 40. The plug body 38 isreleasably secured in the housing 10 by suitable means, such as alocking rod 42 which extends from a location adjacent the exteriorsurface 22a of the lower section 22 through a threaded opening 220 to arecess 22d formed in the flow passageway 16 forming inner wall of thelower housing section 22. The locking rod 42 is provided with threads42a for engaging the housing threads 220 for securing the locking rod 42in the locking position. Mounted exteriorly of the housing 10 is a head42b of the locking rod 42 which is adapted to cooperate with a wrench orthe like in the well known manner from exteriorly of the housing 10 foreffecting rotation of the locking rod 42 to rotate the rod 42 forthreadably engaging or disengaging the threads 22b as desired.Preferably, the rod 42 extends through an opening 38a formed through theplug body 38 for blocking any upward as well as downward movement of theplug body 38. When the rod 42 is withdrawn from the flow passage 16 theplug body 38 is of course released to move from the flow passageway 16into the bore B of the well casing C.

The flow opening or passage 40 of the plug body 38 is provided with anenlarged upper portion 40a which is necked down at 40b to a loweropening portion 40c. The reducing portion 40b forms an upwardly facingannular sealing surface upon which a plug opening closure member or ball44 is adapted to seat. When the ball 44,is.seated (illustrated inphantom in FIG. 1) the plug 38 is actuated so that a greater fluidpressure in the flow passage 16 above the plug body 38 will effect apressure differential across the plug body 38 for moving the plug 38downwardly as is well known in the art. Both the plug body 38 and theball 44 are preferably formed of a drillable material to enableresumption drilling operation after completion of the cementingoperation as is well known. The upper housing 20 as provided with athreaded opening 46 through which the ball may pass when inserted intothe flow passage 16 for actuating the plug body 38 to move in responseto the pressure differential. A threaded plug 48 (FIG. 2) is normallyemployed in the threaded opening 46 to prevent leakage of fluid from theflow passage 16.

OPERATION In the use and operation of the present invention, the wellcasing C to be cemented is positioned at the desired subsurface locationin the well using a drilling rig in a manner well known to those skilledin the art. Circulation of drilling fluid down the bore B of the casingC and up the annulus between the casing in the walls of the well ismaintained through the kelly K and the adapter A by breaking the adaptertool A of the present invention from the casing C at pin threads 12 andadding a desired number of joints to the casing C before making up withthe top of the added joints using the threads 12. In this manner, theoperator will be enabled to maintain drilling fluid circulation with aminimum of delay to prevent the well casing C from becoming stuck in thebore hole.

When the casing C is at the desired location in the well, the source offluid cement is connected to the flow connections 34 and 34a whilemaintaining circulation of the drilling fluid down the bore B of thewell casing C. When it is desired to commence the cementing operations,the fluid cement is introduced into the flow passageway through the flowconnections 34 while reducing the circulation pressure of the drillingfluid in the flow passage F of the kelly K. The increased fluid pressurein the flow passage 16 will then essentially block any additional flowfrom the flow passage F of the kelly K into the flow passage 16 andenable the check valve 36 to move to the closed position. Thereaftergreater fluid pressure in the flow passage 16 in the flow passage F ofthe kelly will tend to maintain the check valve 36 in the closedposition.

The fluid cement introduced into the flow passage 16 by the connections34 and 34a will then flow downwardly through the opening 40 of the plug38 into the bore B of the well casing C where the fluid cement willcirculate downwardly and out the bottom of the well casing C into theannulus. When the predetermined amount of fluid cement to effect thedesired well cementing operation has been communicated into the flowpassage 16 of the housing 10, the fluid pressure in the flow passage 16above the plug 38 and atmospheric pressure is equalized by use of thecementing conduits 35 and 35a valve apparatus. The threaded plug 48 isthen removed to enable dropping of the ball 44 through the opening 46for actuating the plug body and the threaded plug 48 is then replaced.

With the ball present in the flow passage 16 above the plug 38 thecementing flow connectors 34 and 34a are shut-in using the valves of theconduits and 35a and the drilling fluid circulating pumps are then usedto increase the fluid pressure in the passageway F of the kelly K foreffecting opening of the check valve 36 and providing sufiicient flowthrough the opening to seat the ball 44 on the sealing surfaces 40b ofthe opening 40. Prior to or substantially simultaneous with thecommencing to circulate drilling fluid through the flow passage F of thekelly K, the locking rod 42 is removed by effecting rotation thereoffrom exteriorly of the housing 10. With the ball 44 seated on thesealing surface 40b and the rod 42 withdrawn, the plug 38 will commenceto move downwardly in response to the pressure differential across theplug 38. After the plug body 38 has moved down the sufficient distancefor clearance, the rod 42 is replaced to prevent inadvertent leakage offluid through the opening 22c. As is well known, the plug means 36 serveto protect contamination of the fluid cement as it is forced down thebore B of the well casing C by the circulating fluid supplied above theplug body 38 through fluid flow passage F of the kelly K from thecirculating pumps. This pressure is also used to move the plug means 36downwardly in the bore B for forcing the fluid cement into the wellannulus for cementing the well casing within the well.

After the cement has set or hardened sufficiently, it is necessary toremove the adapter housing A from the casing C. If the casing C and theadapter housing A are in a position where they may be grabbed by thetongs of the rotary drilling rig, it is preferable that they be used todisconnect the adapter assembly A from the casing C threads 12. Theadapter housing A then may be held by the tongs to effect disconnectingof the adapter assembly A from the kelly K at threads 14 to enableresumption of drilling operation.

After the adapter housing A is in the location when the cement has setwhere it may not be grasped by the tongs for disconnecting from the wellcasing C. When this occurs, it is only necessary that the set screws 29be loosened to enable the locking ring 28 to drop to the lower orreleased position and then operating the kelly spinner S of the kelly K.Operation of the swivel S imparts a right-hand rotation to the kelly Kwhich effects rotation of the upper housing 20 relative to the lowerhousing 20 for disconnecting at threads 23 and 24. Should disengagementbe particularly difficult, the locking ring 28 may be shifted in themanner previously discussed and secured in the locking position with thelugs 26 for assisting the spinner S in disconnecting the threads 23 and24. With the removal of the upper housing 20, rapid resumption ofoperations for drilling out the concrete plug in the lower end of theplacing C may be commenced without the need to break the lower portionof a housing 22 from the casing C at threaded engagement 12.

By predeterrnining the size of the opening 40 through the plug body 38,it will be readily apparent to those skilled in the art that two movablecementing plugs may be employed during cement operations. The onlyrequirement being that the ball (not illustrated) to actuate the lowerplug (not illustrated) must be able to pass through the reduced portion40c of the upper plug 38.

The foregoing disclosure and description of the invention areillustrative and explanatory thereof, and various changes in the size,shape and materials as well as in the details of the illustratedconstruction may be made without departing from the spirit of theinvention.

I claim:

1. A well conduit adapter for use during cementing of a well conduit ina well, including:

a substantially tubular adapter housing having an upper end and a lowerend;

means mounted with said lower end of said adapter housing for connectingsaid adapter housing with the well conduit to be cemented;

means mounted with said upper end of said adapter housing for connectingsaid adapter housing with a drilling kelly;

said housing having a flow passage extending therethrough forcommunicating the flow passage of the drilling kelly with bore of thewell conduit; and

plug means releasably disposed in said housing and having a closableopening formed therethrough for enabling circulation through saidopening and said flow passage when said plug means is disposed in saidhousing and operable when actuated to move from said housing to reducecontamination of cement moving through said flow passage from saidhousing.

2. The structure as set forth in claim 1, wherein:

said housing having a flow connection communicating with said flowpassage from externally of said housing intermediate said upper and saidlower ends of said housing.

3. The structure as set forth in claim 2, wherein:

said plug means is located in said flow passage between said flowconnection and said lower end of said housing.

4. The structure as set forth in claim 2, wherein:

said housing having an upper section, a lower section and means forreleasably securing said upper and lower sections to form an integralhousing unit capable of supporting the well conduit to be cemented inthe well.

5. The structure as set forth in claim 4, wherein:

said means for releasably securing said upper and lower sectionsincluding a left-hand threaded engagement wherein relative right-handrotation of said housing tends to release said upper and lower sections.

6. The structure as set forth in claim 5, wherein said means forreleasably securing said upper and lower sections further includes:

a plurality of lugs mounted on an exterior surface of said lowerhousing;

a ring member movable along said exterior surface to and from a firstposition engaging said lugs for blocking relative circumferentialrotation between said lower housing and said ring members and a secondposition enabling relative circumferential rotation between said lowerhousing and said ring member, said ring member having a pair ofextensions formed thereon at spaced circumferential locations; and

said upper housing having a pair of protruding members mounted thereonfor engaging said pair of extensions formed on said ring member to blockrelative circumferential rotation between said protruding members andsaid extension wherein relative right-hand circumferential rotationbetween said upper and said lower housing when said ring member engagessaid lugs is blocked.

7. The structure as set forth in claim 2, including:

valve means disposed in said flow passage for blocking flow of fluid insaid flow passage from said upper end of said housing while enablingflow of fluid into said flow passage from said upper end of saidhousing.

8. The structure as set forth in claim 2, wherein said plug meansincludes:

a plug body having an opening of predetermined size formed therethroughfor enabling flow of fluid through the flow passage by said plug body;and

seal means mounted with said plug body for sealing with said housing todirect the flow of fluids through said opening.

9. The structure as set forth in claim 8, including:

means with said housing for releasably securing said plug means withsaid body housing and operable from exteriorly of said housing torelease said plug means for movement through said flow passage.

10. The structure as set forth in claim 8, further including:

said plug body having a sealing surface adjacent said opening; and

a plug opening closure member spaced from said sealing surface forenabling flow of fluid through said opening and movable to seat on saidsealing surface for blocking flow of fluid through said opening toeffect a desired pressure differential upon said plug means foractuating said plug means to move from the flow passage of said housing.

11. The structure as set forth in claim 1, including:

a plug opening closure means to seal said plug opening as desired sothat a greater fluid pressure in said flow passage will effect apressure differential across said plug for moving said plug downwardly.

12. The structure as set forth in claim 11, wherein:

said plug opening closure means includes a seating surface and a closuremember that seats on said seating surface to seal said plug opening toblock said circulation through said plug opening.

13. A well conduit adapter for use during cementing of a well conduit ina well, including:

a substantially tubular adapter housing having an upper end and a lowerend;

means mounted with said lower end of said adapter housing for connectingsaid adapter housing with the well conduit to be cemented;

means mounted with said upper end of said adapter housing for connectingsaid adapter housing with a drilling kelly;

said housing having a flow passage extending therethrough forcommunicating the flow passage of the drilling kelly with bore of thewell conduit;

plug means releasably disposed in said housing for enabling circulationthrough said flow passage and operable when actuated to move from saidhousing to reduce contamination of cement moving through said flowpassage from said housing;

said housing having a flow connection communicating with said flowpassage from externally of said housing intermediate said upper and saidlower ends of said housing;

a plug body having an opening of predetermined size formed therethroughfor enabling flow of fluid through the flow passage by said plug body;

seal means mounted with said plug body for sealing with said housing todirect the flow of fluids through said opening;

said plug body having a sealing surface adjacent said opening; and

a plug opening closure member spaced from said sealing surface forenabling flow of fluid through said opening and movable to seat on saidsealing surface for blocking flow of fluid through said opening toeffect a desired pressure differential upon said plug means foractuating said plug means to move from the flow passage of said housing.

14. A well conduit adapter for use during cementing of a well conduit ina well, including:

a substantially tubular adapter housing having an upper end and a lowerend;

means mounted with said lower end of said adapter housing for connectingsaid adapter housing with the well conduit to be cemented;

means mounted with said upper end of said adapter housing for connectingsaid adapter housing with a drilling kelly;

said housing having a flow passage extending therethrough forcommunicating the flow passage of the drilling kelly with bore of thewell conduit;

plug means releasably disposed in said housing for enabling circulationthrough said flow passage and operable when actuated to move from saidhousing to reduce contamination of cement moving through said flowpassage from said housing;

said housing having a flow connection communicating with said flowpassage from externally of said housing intermediate said upper and saidlower ends of said housing;

said plug means including a plug body having an opening of predeterminedsize formed therethrough for enabling flow of fluid through the flowpassage by said plug body; and

seal means mounted with said plug body for sealing with said housing todirect the flow of fluids through said opening.

15. A well conduit adapter for use during cementing of a well conduit ina well, including:

a substantially tubular adapter housing having an upper end and a lowerend;

means mounted with said lower end of said adapter housing for connectingsaid adapter housing with the well conduit to be cemented;

means mounted with said upper end of said adapter housing for connectingsaid adapter housing with a drilling kelly;

said housing having a flow passage extending therethrough forcommunicating the flow passage of the drilling kelly with bore of thewell conduit;

plug means releasably disposed in said housing for enabling circulationthrough said flow passage and operable when actuated to move from saidhousing to reduce contamination of cement moving through said flowpassage from said housing;

said housing having a flow connection communicating with said flowpassage from externally of said housing intermediate said upper and saidlower ends of said housing; and

said housing having an upper section, a lower section and means forreleasably securing said upper and lower sections to form an integralhousing unit capable of supporting the well conduit to be cemented inthe well.

16. The structure as set forth in claim 15, wherein:

said means for releasably securing said upper and lower sectionsincluding a left-hand threaded engagement wherein relative right-handrotation of said housing tends to release said upper and lower sections.

17. The structure as set forth in claim 16, wherein said means forreleasably securing said upper and lower sections further includes:

a plurality of lugs mounted on an exterior surface of said lowerhousing;

a ring member movable along said exterior surface to and from a firstposition engaging said lugs for blocking relative circumferentialrotation between said lower housing and said ring members and a secondposition enabling relative circumferential rotation between said lowerhousing and said ring member, said ring member having a pair ofextensions formed thereon at spaced circumferential locations; and

said upper housing having a pair of protruding members mounted thereonfor engaging said pair of extensions formed on 'said ring member toblock relative circumferential rotation between said protruding membersand said extension wherein relative right-hand circumferential rotationbetween said upper and said lower housing when said ring member engagessaid lugs is blocked.

1. A well conduit adapter for use during cementing of a well conduit ina well, including: a substantially tubular adapter housing having anupper end and a lower end; means mounted with said lower end of saidadapter housing for connecting said adapter housing with the wellconduit to be cemented; means mounted with said upper end of saidadapter housing for connecting said adapter housing with a drillingkelly; said housing having a flow passage extending therethrough forcommunicating the flow passage of the drilling kelly with bore of thewell conduit; and plug means releasably disposed in said housing andhaving a closable opening formed therethrough for enabling circulationthrough said opening and said flow passage when said plug means isdisposed in said housing and operable when actuated to move from saidhousing to reduce contamination of cement moving through said flowpassage from said housing.
 2. The structure as set forth in claim 1,wherein: said housing having a flow connection communicating with saidflow passage from externally of said housing intermediate said upper andsaid lower ends of said housing.
 3. The structure as set forth in claim2, wherein: said plug means is located in said flow passage between saidflow connection and said lower end of said housing.
 4. The structure asset forth in claim 2, wherein: said housing having an upper section, alower section and means for releasably securing said upper and lowersections to form an integral housing unit capable of supporting the wellconduit to be cemented in the well.
 5. The structure as set forth inclaim 4, wHerein: said means for releasably securing said upper andlower sections including a left-hand threaded engagement whereinrelative right-hand rotation of said housing tends to release said upperand lower sections.
 6. The structure as set forth in claim 5, whereinsaid means for releasably securing said upper and lower sections furtherincludes: a plurality of lugs mounted on an exterior surface of saidlower housing; a ring member movable along said exterior surface to andfrom a first position engaging said lugs for blocking relativecircumferential rotation between said lower housing and said ringmembers and a second position enabling relative circumferential rotationbetween said lower housing and said ring member, said ring member havinga pair of extensions formed thereon at spaced circumferential locations;and said upper housing having a pair of protruding members mountedthereon for engaging said pair of extensions formed on said ring memberto block relative circumferential rotation between said protrudingmembers and said extension wherein relative right-hand circumferentialrotation between said upper and said lower housing when said ring memberengages said lugs is blocked.
 7. The structure as set forth in claim 2,including: valve means disposed in said flow passage for blocking flowof fluid in said flow passage from said upper end of said housing whileenabling flow of fluid into said flow passage from said upper end ofsaid housing.
 8. The structure as set forth in claim 2, wherein saidplug means includes: a plug body having an opening of predetermined sizeformed therethrough for enabling flow of fluid through the flow passageby said plug body; and seal means mounted with said plug body forsealing with said housing to direct the flow of fluids through saidopening.
 9. The structure as set forth in claim 8, including: means withsaid housing for releasably securing said plug means with said bodyhousing and operable from exteriorly of said housing to release saidplug means for movement through said flow passage.
 10. The structure asset forth in claim 8, further including: said plug body having a sealingsurface adjacent said opening; and a plug opening closure member spacedfrom said sealing surface for enabling flow of fluid through saidopening and movable to seat on said sealing surface for blocking flow offluid through said opening to effect a desired pressure differentialupon said plug means for actuating said plug means to move from the flowpassage of said housing.
 11. The structure as set forth in claim 1,including: a plug opening closure means to seal said plug opening asdesired so that a greater fluid pressure in said flow passage willeffect a pressure differential across said plug for moving said plugdownwardly.
 12. The structure as set forth in claim 11, wherein: saidplug opening closure means includes a seating surface and a closuremember that seats on said seating surface to seal said plug opening toblock said circulation through said plug opening.
 13. A well conduitadapter for use during cementing of a well conduit in a well, including:a substantially tubular adapter housing having an upper end and a lowerend; means mounted with said lower end of said adapter housing forconnecting said adapter housing with the well conduit to be cemented;means mounted with said upper end of said adapter housing for connectingsaid adapter housing with a drilling kelly; said housing having a flowpassage extending therethrough for communicating the flow passage of thedrilling kelly with bore of the well conduit; plug means releasablydisposed in said housing for enabling circulation through said flowpassage and operable when actuated to move from said housing to reducecontamination of cement moving through said flow passage from saidhousing; said housing having a flow connection communicating with saidflow passage from exteRnally of said housing intermediate said upper andsaid lower ends of said housing; a plug body having an opening ofpredetermined size formed therethrough for enabling flow of fluidthrough the flow passage by said plug body; seal means mounted with saidplug body for sealing with said housing to direct the flow of fluidsthrough said opening; said plug body having a sealing surface adjacentsaid opening; and a plug opening closure member spaced from said sealingsurface for enabling flow of fluid through said opening and movable toseat on said sealing surface for blocking flow of fluid through saidopening to effect a desired pressure differential upon said plug meansfor actuating said plug means to move from the flow passage of saidhousing.
 14. A well conduit adapter for use during cementing of a wellconduit in a well, including: a substantially tubular adapter housinghaving an upper end and a lower end; means mounted with said lower endof said adapter housing for connecting said adapter housing with thewell conduit to be cemented; means mounted with said upper end of saidadapter housing for connecting said adapter housing with a drillingkelly; said housing having a flow passage extending therethrough forcommunicating the flow passage of the drilling kelly with bore of thewell conduit; plug means releasably disposed in said housing forenabling circulation through said flow passage and operable whenactuated to move from said housing to reduce contamination of cementmoving through said flow passage from said housing; said housing havinga flow connection communicating with said flow passage from externallyof said housing intermediate said upper and said lower ends of saidhousing; said plug means including a plug body having an opening ofpredetermined size formed therethrough for enabling flow of fluidthrough the flow passage by said plug body; and seal means mounted withsaid plug body for sealing with said housing to direct the flow offluids through said opening.
 15. A well conduit adapter for use duringcementing of a well conduit in a well, including: a substantiallytubular adapter housing having an upper end and a lower end; meansmounted with said lower end of said adapter housing for connecting saidadapter housing with the well conduit to be cemented; means mounted withsaid upper end of said adapter housing for connecting said adapterhousing with a drilling kelly; said housing having a flow passageextending therethrough for communicating the flow passage of thedrilling kelly with bore of the well conduit; plug means releasablydisposed in said housing for enabling circulation through said flowpassage and operable when actuated to move from said housing to reducecontamination of cement moving through said flow passage from saidhousing; said housing having a flow connection communicating with saidflow passage from externally of said housing intermediate said upper andsaid lower ends of said housing; and said housing having an uppersection, a lower section and means for releasably securing said upperand lower sections to form an integral housing unit capable ofsupporting the well conduit to be cemented in the well.
 16. Thestructure as set forth in claim 15, wherein: said means for releasablysecuring said upper and lower sections including a left-hand threadedengagement wherein relative right-hand rotation of said housing tends torelease said upper and lower sections.
 17. The structure as set forth inclaim 16, wherein said means for releasably securing said upper andlower sections further includes: a plurality of lugs mounted on anexterior surface of said lower housing; a ring member movable along saidexterior surface to and from a first position engaging said lugs forblocking relative circumferential rotation between said lower housingand said ring members and a second position enabling relativecircumferentiAl rotation between said lower housing and said ringmember, said ring member having a pair of extensions formed thereon atspaced circumferential locations; and said upper housing having a pairof protruding members mounted thereon for engaging said pair ofextensions formed on said ring member to block relative circumferentialrotation between said protruding members and said extension whereinrelative right-hand circumferential rotation between said upper and saidlower housing when said ring member engages said lugs is blocked.